code: def reset_lstm(lstm):
      # in order to run fprop multiple times
      # for the gradient check tests the
      # lstm internal variables need to be
      # cleared
      lstm.x = None
      lstm.xs = None  # just in case
      lstm.outputs = None
      return
  
file_path: neon/tests/test_lstm.py
imports: import itertools
  import numpy
  from neon import NervanaObject, logger
  from neon.initializers.initializer import Constant, Gaussian
  from neon.layers.recurrent import LSTM
  from neon.layers.container import DeltasTree
  from neon.transforms import Logistic, Tanh
  from lstm_ref import LSTM
  from utils import sparse_rand, allclose_with_out
label_desc: Use image node_id 5 for calling a global function with example usage: reset_lstm(lstm) without return types